1. Field of the Invention
The present invention relates to a bicycle crank mechanism, and more particularly to a mechanism for attaching a pedal to a crank arm.
2. Description of the Related Art
In a conventional bicycle, a pedal is rotatably attached to a crank arm through a pedal shaft. The pedal is only rotatable relative to the pedal shaft.
During a down stroke of the crank arm, it is easy for the rider to exert a treading force if the arch of his or her foot lies directly over the pedal shaft. During an up stroke of the crank arm, the pedal is easy to pull upward if the forward end of the rider's foot is close to the pedal shaft particularly where the rider's shoe is fixed to the pedal through a cleat. Thus, there is room for improvement in the conventional bicycle which does not allow a to-and-fro motion of the pedal relative to the pedal shaft.